Abstract We have analyzed the galaxy number density and luminosity density profiles
of rich clusters of galaxies from redshifts to .
We show that the luminosity profile computed with bright galaxies
(MR < -21) is significantly cusped in the center of the clusters, whatever
the redshift. This is in agreement with the dark matter profiles predicted by
numerical simulations. The galaxy number density profile for the bright
galaxies is fitted equally well with a core model or a cusped model. In
contrast, the luminosity and the galaxy number density profiles of the fainter
galaxies are significantly better fitted by a core model.
We did not detect any statistically significant different fits when applied to
data in the
range from to . The difference in profile between
faint and bright galaxies may be due to the rapid
(relative to the age of the universe at z=0 versus z=0.5) destruction of
the faint galaxies by tidal forces and merging events in the denser central
regions of the clusters. This process could erase the cusp by turning faint
galaxies into diffuse light. In this case, the galaxies (with a cusp visible
in the bright galaxy number density and mainly in luminosity profiles) would
trace the total mass distribution.